[moderation] [scsi?] KCSAN: data-race in sg_common_write / sg_finish_rem_req (5)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: b4432656b36e Linux 6.15-rc4
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10316368580000
kernel config: https://syzkaller.appspot.com/x/.config?x=6bd11c5d4ce102b4
dashboard link: https://syzkaller.appspot.com/bug?extid=0e7d81703b9f895856dc
compiler: Debian clang version 20.1.2 (++20250402124445+58df0ef89dd6-1~exp1~20250402004600.97), Debian LLD 20.1.2
CC: [James.B...@HansenPartnership.com dgil...@interlog.com linux-...@vger.kernel.org linux...@vger.kernel.org martin....@oracle.com]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/621ff6c87f4d/disk-b4432656.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/df50df95c16b/vmlinux-b4432656.xz
kernel image: https://storage.googleapis.com/syzbot-assets/665a331c65b4/bzImage-b4432656.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0e7d81...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in sg_common_write / sg_finish_rem_req

write to 0xffff88810794131d of 1 bytes by task 3382 on cpu 1:
sg_unlink_reserve drivers/scsi/sg.c:2061 [inline]
sg_finish_rem_req+0x11f/0x270 drivers/scsi/sg.c:1843
sg_rq_end_io_usercontext+0x38/0x1c0 drivers/scsi/sg.c:1302
process_one_work kernel/workqueue.c:3238 [inline]
process_scheduled_works+0x4cb/0x9d0 kernel/workqueue.c:3319
worker_thread+0x582/0x770 kernel/workqueue.c:3400
kthread+0x486/0x510 kernel/kthread.c:464
ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff88810794131d of 1 bytes by task 5122 on cpu 0:
sg_start_req drivers/scsi/sg.c:1783 [inline]
sg_common_write+0x961/0xc30 drivers/scsi/sg.c:799
sg_new_write+0x7b6/0x890 drivers/scsi/sg.c:766
sg_ioctl_common drivers/scsi/sg.c:931 [inline]
sg_ioctl+0xb81/0x1360 drivers/scsi/sg.c:1156
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:906 [inline]
__se_sys_ioctl+0xcb/0x140 fs/ioctl.c:892
__x64_sys_ioctl+0x43/0x50 fs/ioctl.c:892
x64_sys_call+0x19a8/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:17
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xd0/0x1a0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x01 -> 0x00

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 5122 Comm: syz.2.620 Not tainted 6.15.0-rc4-syzkaller #0 PREEMPT(voluntary)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.